First off, hi! You might get some unfriendly replies since these kinds of questions are really common here and you're asking things that can't really be answered without making huge generalizations. Before I answer your questions, I have a few for you.
What do you plan to do in Japan? Are you planning to go to college? If you answer "no", then it's very difficult to move to Japan unless you marry a Japanese person and get a spousal visa. Why? Because you need either a bachelor's degree or 10 years of specialized work experience in order to qualify for a work visa. You could get a student visa, but that also comes with restrictions on work.
What do you mean you will "very soon learn how to speak Japanese"? I started learning Japanese around your age in university and I was very, very bad at it. I'm pretty fluent now, but that's after living in Japan for five years and using it every day. You might be one of those people who learns great from a textbook or maybe you have someone who is fluent that you can practice with, so it might come easier to you than it did for me. Just keep in mind that even after you become fluent, you will never know Japanese to the same degree of fluency as a native speaker because you're starting as an adult.
Don't worry too much though. It's not that hard to reach a point of conversational fluency if you are exposed to the language every day. But it helps to be realistic about how much time it takes. So don't feel discouraged if you still can't express yourself or read most things after a year of study.
Okay, now to your questions.
My question is how different is living in Japan compared to the U.S? What sort of answer are you looking for? I can't even compare most states within the US without making huge generalizations. But I'll try. If you're in the working/middle class now, then the standard of living won't be much different. The working hours are generally longer if you're a full-time employee, but you can get away with a lot as a foreigner since you probably won't be held to the same standards. In general, Japan is safer than the US. More people rely on public transport and cars and gas are more expensive. Food and drinking culture is different, but you can still find plenty you're familiar with. The biggest obvious difference will be that 99% of the people around you will be Japanese, speak Japanese, and most of everything written will be Japanese. You will have to adapt to Japan or leave, because Japan will not change itself for you.
Also is there any racism? I'm hispanic so would I be looked at any differently besides the stimga of being a foreinger? Yes and no. I feel like "racism" it thrown around too much by Americans because we make a huge deal out of it and pretend like making generalizations about people is the worst thing ever. The fact is, most people in Japan have not had any meaningful interactions with foreigners and that leads to a lot of ignorance about foreign people. People will probably comment about you, stare at you, ask insensitive questions, and maybe talk to you in a very patronizing way if you don't speak much Japanese. Some people are unfriendly, but every country has assholes. I've never really encountered anyone who treated me badly because I'm a foreigner, but I know some people go out of their way to avoid interacting with me because they have no idea how to deal with foreigners.
You will never be accepted as "Japanese", though, if that's what you're asking.
I'm not sure if this is the kind of information you're looking for, but feel free to ask more specific questions if you have any. I don't regret moving to Japan, but I would be wary about making your future extremely Japan focused. I wish I studied something more marketable instead of Japanese before I came since I learned way more after I got here than I did in school.